11 Jul
2024
11 Jul
'24
5:14 a.m.
On Wednesday, July 10th, 2024 at 4:00 PM, John Levine <johnl(a)taugh.com> wrote:
It appears that Al Kossow aek(a)bitsavers.org said:
Attempting once again to COFF this thread as I am quite interested in the
discussion of this sort of emulation/simulation matter outside of the
confines of UNIX history as well.
To add to the discussion, while not satisfying the question of "where did
this sort of thing begin", the 3B20 was another machine that provided some
means of emulating another architecture via microcode, although what I know
about this is limited to discussions about emulating earlier ESS machines
to support existing telecom switching programs. I've yet to find any
literature suggesting this was ever used to emulate other general-purpose
computers such as IBM, DEC, etc. but likewise no suggestion that it *couldn't*
be used this way.
- Matt G.
On 7/10/24 1:53 PM, Dan Cross wrote:
> The idea of writing simulators for machines clearly dates to before
> (or near) the beginning of TAOCP.
Sure, but the topic of interest here is compiling machine code from one
machine to another. You know like Rosetta does for x86 code running on
my Macbook (obUnix: whose OS is descended from FreeBSD and Mach and does
all the Posix stuff) which has an M2 ARM chip.
We know that someone did it in 1967 from 709x to GE 635, which I agree
was quite a trick since really the only thing the two machines had in
common was a 36 bit word size. I was wondering if anyone did machine
code translation as opposed to instruction at a time simulation before that.